1. Background of the Invention
The present invention relates generally to an I-beam or channel construction and, more particularly, to such an I-beam or channel having a web of reduced cross-sectional dimensions and enhanced strength, and a method of making the same.
2. Description of Related Art
I-beams or channel beams are well known especially in the building industry for providing the basic support of the entire structure, which beams include first and second relatively flat flanges held separated and generally parallel to one another by an intervening wall member connecting the two flanges, the latter most frequently referred to as a "web". To enhance ultimate use and to reduce manufacturing costs, it is desirable to be able to produce such beams which are optimally light-weight for a given bearing strength. Typically, a beam can be made lighter by merely reducing the web thickness, however, if nothing else is done the bearing strength of the beam will be reduced which in the extreme could cause the beam to buckle or collapse during use.
In U.S. Pat. No. 4,251,973 there is provided an I-beam or channel having a central region of the web deformed into a set of corrugations which extend along the beam length. This patented construction substantially increases the strength of the beam beyond that which would typically be achieved by merely leaving the web in its normal flat condition. Accordingly, this offers the ability to reduce the beam weight from more conventional designs and yet not sacrifice beam bearing load capabilities. Although the referenced patent provides a substantially superior beam for bearing strength from that which can be produced using an unmodified web of uniform thickness, it is desirable to be able to reduce beam weight even further without decreasing beam strength, or even to increase beam strength.